1. Technical Field
The present invention relates to a projector.
2. Related Art
There has been known a projector that modulates with an optical modulator a light beam irradiated by a light source in accordance with image information to form an optical image and projects the optical image in an enlarged manner.
Such a projector includes an integrator illumination optical system for separating the light beam irradiated by the light source into sub light beams to superpose the sub light beams onto an illuminated area of the optical modulator.
The integrator illumination optical system includes a plurality of optical elements such as a second lens array and a polarization converter. In order to prevent misalignment between the optical elements and to simplify manufacture of the projector, there has been proposed an integrator illumination optical system in which the optical components are housed in a frame as a unit (see, for instance, Document: JP-A-11-242186).
In a projector disclosed in the Document, the second lens array, a light shield plate and the polarization converter are arranged from the upper stream side in a light-beam traveling direction, these optical elements positioned relative to each other and fit in the frame of the unit.
However, the projector disclosed in the Document uses the frame to form the integrator illumination optical system as a unit, which increases the size and the number of components of the integrator illumination optical system. In addition, the light shield plate is disposed between the second lens array and the polarization converter, and therefore a clearance for the light shield plate is required between the second lens array and the polarization converter, which causes the size of the integrator illumination optical system to be increased. Since the optical elements are fixed to each other via the frame, misalignment might occur in relative positions of the optical elements.